Effect of Supplementary Cementitious Admixtures on Hardened Concrete

Effect of Supplementary Cementitious Admixtures on Hardened Concrete

Quality Measure  vs Effect

Strength : Fly ash increases ultimate strength, but reduces rate of strength gain. Silica fume has less effect on rate of strength gain than pozzolans.

Drying Shrinkage and Creep : Low concentrations usually have little effect. High concentrations
of ground slag or fly ash may increase shrinkage. Silica fume may reduce shrinkage.

Permeability and Absorption : Generally reduce permeability and absorption. Silica fume is especially effective.

Alkali–Aggregate Reactivity :  Generally reduced reactivity. Extent of improvement depends on
type of admixture.

Sulfate Resistance : Improved due to reduced permeability.